Written by: on March 29, 2021 @ 8:00 am

Join High Touch High Tech in celebrating
Find a Rainbow Day
April 3rd

Image Source: Pixabay.com

A rainbow is caused by the collision of sunlight and certain atmospheric conditions. Light enters a water droplet, slowing down and bending as it goes from air to denser water. The light reflects off the inside of the droplet, separating into its component wavelengths–or colors. When light exits the droplet, it makes a rainbow.

Now that you know the science behind rainbows, now we need to figure out a way to remember all those colors! Allow me to introduce you to my friend, Roy G. Biv. He is not a real person, but his name is the acronym that helps us remember the colors of the rainbow, or in more precise science terms, the colors that make up the visible light portion of the electromagnetic spectrum! The colors are Red, Orange, Yellow, Green, Blue, Indigo, and Violet.

Have you seen this fun video by They Might Be Giants? It teaches you about ROY G BIV & the electromagnetic spectrum!

ROY G BIV – They Might Be Giants

Rainbows have held incredibly special meaning to people, forever. In fact, the rainbow flag was created and became known as the gay or LGBTQ symbol for lesbian, gay, bisexual, transgender, and queer (LGBTQ) pride and LGBTQ social movements. Rainbow flags have also served as a symbol of peace.

Image Source: Wikimedia Commons

But there are many myths and folklores surrounding rainbows. Here are some of the more common tales and beliefs about rainbows:

  • Biblical accounts establish the rainbow as a covenant, or promise, between God and every living creature, that the earth will never again be destroyed by flood.
  • In Greek mythology rainbows were thought to be a path between Earth and Heaven. The rainbow was called the “Bridge” in Norse mythology, connecting Asgard, the home of the gods with Midgard, the home of humans.
Image Source: Wikimedia Commons
Bifrost “Rainbow Bridge” from Asgard to Midgard
  • A pot of gold at the end of every rainbow that is guarded by a tricky leprechaun. The legend goes like this… Once upon a time, the Vikings lived in Ireland, looting, and plundering as they pleased, then burying their ill-gotten treasures all over the countryside. When they eventually departed from the Emerald Isle, they inadvertently left behind some of their booty, which the leprechauns found. Now, the leprechauns knew the Vikings had gotten their treasures through stealing, which was wrong. This bad behavior made the leprechauns mistrust all people, Viking or not. To ensure no humans could take what they now considered their gold, the leprechauns reburied it in pots deep underground all over the island. When rainbows appear, they always end at a spot where a leprechaun’s pot of gold is buried.
Image Source: Pixabay.com

Have you ever wondered if there are different kinds of rainbows? There are 12 different types of rainbows. When you see the typical rainbow that forms after a storm, you may think that is all there is to it. But in truth, there are all sorts of rainbows—some rarer than others. Each type of rainbow is created under different circumstances and falls either into primary or secondary types.

Have you ever heard of a Fogbow? A fogbow is a type of rainbow that occurs when fog or a small cloud experience sunlight passing through them. The droplets of moisture from the fog work to diffract that light. This type of rainbow is usually found in places where the fog in the air is thin. It can also form above any body of water. Typically, this rainbow consists of blue, white, and red. Much of a fogbow rainbow is white, with blue appearing on the inside and red appearing at both ends.

Image Source: Wikimedia Commons

Have you ever heard of a moonbow? A lunar rainbow (aka “moonbow”) is an unusual sight. This event occurs on the moon during a lunar month. The moon must be almost fully lit up for this type of rainbow to form. When it does, it appears as a white arc. Lunar rainbows line the moon’s outer rim. They are dull in appearance because the light on the moon is not as bright as the light on earth.

Image Source: Wikimedia Commons

Can we have more than one rainbow at a time? Yes, they are called multiple rainbows. One of the rarest forms is multiple, or double, rainbows. They occur when several rainbows form in the same place at the same time. It takes at least one primary rainbow to generate this sight, as well as several other secondary rainbows. There is always space in between each one.

Image Source: Wikimedia Commons
Double Rainbow

This space is referred to as Alexander’s Band. In around 200 AD, Alexander of Aphrodisius observed that, during rain, the area between primary and secondary rainbows appears considerably darker than the surrounding sky. The phenomenon occurs because the refractive index of light means that light from raindrops in the region of the sky between the two rainbows cannot reach the observer. When sunlight is reflected in raindrops, a double reflection occurs. White light reflects off the colors of the primary rainbow, creating secondary ones.

There are even twin rainbows! A twinned rainbow is also a rare sight to see. Though they have one base in common, two rainbows are formed, with one being primary and one being secondary. The colors of both rainbows are seen in the same sequence. When two rain showers occur, the size of the raindrops can lead to the formation of a twinned rainbow. With different shaped and sized raindrops from each storm, one rainbow becomes two. In an even rarer sight, a twinned rainbow can include the formation of as many as three.

Image Source: Wikimedia Commons

Can the shape of rainbows change, or are they always an arc? Rainbows can change shapes, some can even be a full circle. In most cases, rainbows are semicircular arcs. Yet on rare occasions, it is possible to spot a full circle rainbow. This type of rainbow typically occurs in high altitude areas. At lower altitudes, the position of the sun prevents a full circle from being formed. Anything obstructing the sun also makes it impossible for this type of rainbow to form. When it does, it may include both primary and secondary rainbows.

Image Source: Wikimedia Commons
Full Circle Rainbow

Check out this video of a full circle rainbow here:

Rainbows have long been a source of mystery and wonder. Next time you see a rainbow, what will you wonder about?

If you love rainbows as much as we do, you could see one anytime you like with our At-Home Bubble Atmosphere experiment. Click links below for the lesson plan and tutorial video!

Lesson Plan: https://sciencemadefun.net/downloads/bubble_atmosphere.pdf

Tutorial Video: https://youtu.be/ajhu3MO7RIA

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